Download VirtualBox
- Download and install Virtualbox for Mac here, and the extension pack, here.
- Get the Catalina offline installer to your Mac’s Applications folder, and MacOS ISO for Virtualbox (optional).

Get the installation script
- Download Alexander’s macOS Virtualbox script from Github, here. Then extract the ZIP file to “macoscatalinavirtualbox” folder on desktop.

Run the commands
- Open Terminal app in macOS High Sierra or the host OS and run the following commands in the order.
- Install the Xcode command line developer tools when you see the prompt on the screen.

Follow the script prompts
Let the script create the installation files. Enter your system password in Terminal if requested.
Remove the installer from boot order
When the first installation stage ends, press Enter as prompted to remove the CDR disk image from the boot order. Leaving it connected can cause an installation loop.
Finish installation
Terminal restarts VirtualBox. Allow the final macOS installation stage to complete.

How to run macOS Catalina on Virtualbox
For me, it took nearly 1 hour to install macOS Catalina on Virtualbox for Mac on an SSD iMac 2011 variant. The Terminal app may look unresponsive at times, depending on your system speed. But if you follow the steps and give enough time, Virtualbox will boot into Catalina, as shown in the first image.

Check the above video to see macOS Catalina running on our Mac that has High Sierra as the primary OS. We won’t tell you how to install macOS Catalina on Virtualbox for Windows (for legal reasons), but you can, of course, use the hints here.
What happens after running the script?
Now the script will automate the process of installing macOS Catalina on Virtualbox. However, it may require manual actions at certain steps of installation. Input the system password on Terminal if required, while it makes macOS DMG and ISO files for the virtualisation. When macOS Catalina installer ends first stage of installation, press the Enter key for removing the disc image(.CDR) from the boot order. It will cause an installation loop if you do not disconnect the Catalina ISO or CDR disc at this point.
How long did installation take?
For me, it took nearly 1 hour to install macOS Catalina on Virtualbox for Mac on an SSD iMac 2011 variant. The Terminal app may look unresponsive at times, depending on your system speed. But if you follow the steps and give enough time, Virtualbox will boot into Catalina, as shown in the first image.
For me, it took nearly 1 hour to install macOS Catalina on Virtualbox for Mac on an SSD iMac 2011 variant. The Terminal app may look unresponsive at times, depending on your system speed. But if you follow the steps and give enough time, Virtualbox will boot into Catalina, as shown in the first image.
Check the above video to see macOS Catalina running on our Mac that has High Sierra as the primary OS. We won’t tell you how to install macOS Catalina on Virtualbox for Windows (for legal reasons), but you can, of course, use the hints here.
Complete installation
Now the script will automate the process of installing macOS Catalina on Virtualbox. However, it may require manual actions at certain steps of installation. Input the system password on Terminal if required, while it makes macOS DMG and ISO files for the virtualisation. When macOS Catalina installer ends first stage of installation, press the Enter key for removing the disc image(.CDR) from the boot order. It will cause an installation loop if you do not disconnect the Catalina ISO or CDR disc at this point.
Terminal will restart the Virtualbox when you press the Enter key and final step of the macOS Catalina installation starts, and it last for about 10-15 minutes. This method for running macOS on Virtualbox may also also be used install& run 32-Bit apps on Catalina.



